Glow switch



Patented Nov. 29, 1 949 UNITED STATES PATENT OFFICE GLOW SWITCH Francis D. Graham, West Orange, NTJ.

Application March 29, 1949 Serial No. 84,147

7' Clams. 1-

This` invention relates to aglow switch, and has for an object to provide a' glow switch that is non-chatterng. A gl ow Starter switch is used for electric clischarge. lamps and comprises a discharge tube for connection between the lamp eiectrodes and in: which a gl'ow discharge heats a bimetallic which isi thus caused to bend and close Contacts. The closureof the Contacts causes the glow discharge to cease so that the Contacts open thereby breaking a circuit containing reactance. The resulting voltage surge causes a discharge in the lamp to start.

When the. giow discharge ceases, the bimetall-ic strip cools relatively slowly the Contacts open relatively slowly and. there is a tendency for the Contacts to are, thus reheating' the bimetallic strip in the circuit, reclosing the circuit, then reopening again in a continuous chatter resulting from the arcing and: reheating of the metallic strip the circuit.

It is an object of this inventiontoremovethe bmetall ic strip from the circuit when the circuit iscompleted so that whenthe inevitable arcing occu rs itdoes notreheat the bimetalli'c strip; and there is no chattering with resulting unsatisfac tery operation of the electric disch-arg-elamp it is cc-ntrollin-g.

A further object of this invention is to provide a non-chattering glow Starter switch wherein a bimetallic strip oauses the electrodes to close a circuit', without i-t being itself part of the final* circuit, and wherein arcing as' the circuit reopens does not reheat the b-imetallic strip.

A further object of this invention is to provide a glow Starter switch wherein there` is a thermal and; Electric sonda-:tor connected to the electrode or contact carried by the bimetallic strip, which conductor both carries the electric current andi conducts the hoat caused by arcing away from the electrode without going directly through the bimetaliic strip, thus permitting the switch to posi'- tively reopen as desired without any chattering.

A still further object of this invention is to provide a non-ohattering giow switch that is positive in action, yet is simple and relatively inexpensive to construct, and does not involve any complicated elements that both add to the cost of construction and possibiiity of improper operation.

The foregoing and other objects of the inventicn will become more apparent as the description proceeds with the aid of the accompanying drawing, in which:

Fig. 1 is a sectional View through a switch glass (CI. ZUG- 1135) 2 envelope showing the details of the glow switch, and

Fig. 2 is a similar view of another form.

There is' shown at IG' the usual sealed glass envelope having the usual internal boss I. f through which extends the conductors iz. and 3 connected to the electrode posts M and` [5. Mounted on the electrode post M as' by welding is the customary bimetallic strip I'6, which in operation the conventi'onaf glow switch, would complete its circuit with the electrode post !5. In` this inVen-tion, however, a link ll is Secured' on the end of the bimetallic strip I'B and in turn has mounted on its other end an insulation head; i& of' glass or other insu-l'ation materia-1.

Also Secured' on the bead' I & but spaced from thelink FF is' a stubelectrode or contact 20- which projects slightly toward the electrode post !5. Attached to` this' stub= electrode or contact 23- is a conductor 21, which, in the formin Fig. 1', has its other end attached to the electrode` post M' at 2-2- with-in the glass' envelope but at a substantial distance from the bimetallic strip Hi.

In' the form in Fig. 2, the conductor ZI" is not connected` directly to the bimetallic electrode post,. but instead, is connected at 23 to a third' post 24 extend-n-g through the gl ass envelope boss H" andcon-neeted at 25 to' the conductor 12", the other parts in Fig. 2 being identical with those in Fig. 1.

In operation, instead of the end of the bimetallic strip com-pleting the circuit with the electrode post l5 the bim'etal-l ic strip is not at al-l inthe electric circuit when the circuit is completed, but instead the stub electrode or contact 20, carried thereby via the beati l 8-, closes the circuit' when the glow beats up the bimetallic strip !Su The electric circuit is completed through the electrode post IE to the. stub electrode or contact 20, the conductor 21, through. connection: 22 to the electrode post M and through the conductor.

In Fig. 2, the circuit is. completed through conductor 21' to point 23; and third post 26 and through connection 25 to the conductor I2'.

In operation, when the voltage is applied, a glow takes place at the electrodes and the bimetallic strip !6 within the envelope lil, heating the electrodes and the bimetallic strip. This heating of the bimetallic strip !6 causes the U of the bimetallic strip li to open, moving its head IB and contact end until the stub electrode or contact 26 Contacts the electrode post [5.

As the circuit is closed by the stub electrode post or contact 20 Contacting electrode post 5,

u the glow in the bimetallic strip |6 is discontinued,

thus ceasing to heat the bimetallic strip IS, and allowing it to contract again, thus breaking the circuit between electrode post and the stub electrode or contact 20. As the stub electrode or contact 2@ moves away from the electrode post !5, any arcing that may occur will occur between the electrode post !5 and the stub electrode or contact 20. The heat from such arcing will not heat the bimetallic strip !6 because of the presence of the non-conducting glass bead l8, and instead, the heat will flow along the conductors 2! to the electrode post !4, in Fig. 1, at a point 22 suba U-shaped bimetallic strip mounted on one post stantially removed from the bimetallic strip 16 and in Fig. 2, to the third electrode post and thus at 25 to the conductor 12', even more re moved from the vicinity of the bimetallic strip !6. Thus, there is no possibility of reheating of the bimetallic strip !6 by any arcing, and hence it will continue to cool and move the stub e1ec-: trode or contact 20 away from the electrode post l5, and no chattering can take place.

Since certain further changes can be made in the foregoing constructions, and different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter shown in the accompanying drawing or described hereinbeiore shall be interpreted as illustrative, and not in a limiting sense.

What is claimed is:

1. A non-chattering glow Starter switch comprising a sealed impervious envelope and a pair of electrode posts extending into said envelope, a bimetailic strip mounted at one end on one of said posts and arranged to extend toward the other of the posts, an insulating member linked to the free end of said bimetallic strip, a stub electrode mounted on said insulating member and arranged to contact the other post as the bimetallic strip is extended, and a conductor member thermally and electrically connecting said stub electrode to the bimetallic strip mounted electrode post at a point substantialiy remote from the bimetailic strip mounting thereon.

2. A non-chattering glow Starter switch comprising a sealed impervious envelope and a pair of electrode posts extending into said envelope, a bimetallic strip mounted at one end on one of said posts and arranged to extend toward the other of the posts, an insuiating member linked to the free end of said bimetallic strip, a stub electrode mounted on said insulating member and arranged to contact the other post as the bimetallic strip is extended, and a conductor member thermally and electrically connecting said stub electrode to the bimetallic strip mounted electrode post at a point 7 substantially remote from the bimetallic strip mounting thereon, said thermal and electricai conducting member including a third post eX- tending through the envelope and connecting to' said bimetallic post outside of said envelope.

3. A non-chattering glow starter switch comprising a sealed impervious envelope and a pair of electrode posts extending into said envelope, a U-shaped bimetallic strip mounted at one end on one of said posts and arranged to extend toward i 'and arranged to extend its free end toward the other post; means for providing a non-chattering contact between said electrode posts comprising a contact member carried by but insulated from the free end of the bimetallic strip and a thermal and eiectrical conductor connecting said contact member to the electrode post, on which the bimetallic strip is mounted, at a point remote from the strip mounting.

5. In a glow Starter switch having a sealed glass envelope containing a pair of electrode posts and a U-shaped bimetallic strip mounted on one post and arranged to extend its free end toward the other post; means for providing a non-Chaty tering contact between said electrode posts comprising a contact member carried by but insu iated from the free end of the bimetallic strip and a thermal and electrical conductor connecting said contact member to the eiectrode post, on which the bimetallic strip is mounted, at a point remote from the strip mounting, said remote point being outside of the envelope.

6. In a glow starter switch having a sealed glass envelope containing a pair of electrode posts and a U-shaped bimetallic strip mounted on one post and arranged to extend its free end toward the other post; means for providing a non-chattering contact between said electrode posts comprising a contact member, an insuiating bead carried by the ree end of the bimetalhc strip, said contact member being mounted on said insulating bead,

1 and a thermal and electrical conductor connecting said contact member to the electrode post, on which the bimetallic strip is mounted, at a point remote from the strip mounting.

7. In a glow Starter switch having a sealed glass envelope containing a pair of electrode posts ana a U-shaped bimetallic strip mounted on one post and arranged to extend its free end toward the other post; means for providing a non-chattering contact between said electrode posts comprising a contact member, an insuiating bead carried by the free end of the bimetallic strip, said contact member being mounted on said insulating bead, and a thermal and electrica] conductor connecting said contact member to the electrode post, on

which the bimetailic strip is mounted, at a point remote from the strip mounting, said remote point being outside of the envelope.

FRANCIS D. GRAHAM.

No references cited. 

